This scene uses spectral data which is discretized & supplied to a Microfacet BRDF with a Fresnel conductor operator. This allows us to render materials like Gold, Silver, Copper etc. and pretty much any alloy or metal. There is also a roughness applied with a Trowbridge Reitz microfacet distribution.

The floor is a matte material with a diffuse, normal and roughness map. Roughness is used by the Oren-Nayar operator in the Lambertian BRDF. If we supply roughness as 0, the Oren-Nayar behaves as a perfect diffuse material.